New Insights into the Lithium-rich Low-mass Evolved Stars

Lithium (Li) has confused scientists for decades at almost every scale of the universe. One percent of low-mass evolved stars have anomalously high Li abundances in their atmospheres, conflicting directly with the prediction of standard stellar evolution models. This finding makes the production and evolution of Li in the Universe more intriguing, not only in the sense of Big Bang nucleosynthesis or the interstellar medium, but also for the evolution of stars. Decades of effort have been put into explaining why such extreme objects exist, yet the origins of Li-rich giants are still being debated. As one of most powerful spectra collecting facility in the world, LAMOST has found a large number of such objects. Combing those spectra with the data from asteroseismology and high-resolution observations, we are gaining the new insights of the Li-rich low-mass evolved stars, which will eventually push our understanding to this element and its evolution in our Galaxy a step forward. In this report, I will briefly introduce what did we know about the Li-rich low-mass evolved stars from the past, show what was learned from the recent studies, and then discuss about the new questions that need to be addressed in the future.

Hongliang Yan (NAOC)
Subo Dong
Thursday, April 22, 2021 - 4:00PM to Thursday, April 22, 2021 - 5:00PM
Dr. Hongliang Yan got his bachelor degree from the Nanjing University, and then the doctor degree on astrophysics from University of Chinese Academy of Sciences. He used to work at the Apache Point Observatory and Institute of Astronomy in Russian Academy of Sciences as a visiting scholar. Since 2016, he has been working for National Astronomical Observatories of CAS as one of the key members of LAMOST operation team. His main research interest in the stellar chemical abundance and Galactic chemical evolution. Recently, he is focusing on the lithium abundance in the low-mass evolved stars, and got a series of interesting results on this topic. His research is funded by the Excellent Young Scientists Fund from NSFC, the Youth Innovation Promotion Association of CAS, and the NAOC Nebula Talents Program.